Tool for releasing frozen work parts

ABSTRACT

A tool for forcibly releasing interlocked work parts, such as a frozen piston from a disc-brake caliper. The tool includes a first, separable, rigid tool part for engagement with one work part, one-piece rigid,second tool part in engagement with the other work part, and a connector means connected between the first and second tool parts and including screw means for axially adjusting the first and second tool parts toward one another to separate the interlocked work parts.

United States Patent [1 1 Racin H Oct. 2, I973 [54] TOOL FOR RELEASING FROZEN WORK 3,166,834 H1965 Newman 29/263 X PARTS 3,408,724 ll/l968 Hoeijenbos 29/263 [75] Inventor: George Racin, Akron, Ohio Primary Examiner Andrew R Juhasz [731 Assignees: Michael Racin; Donald A. Reynolds, As s a t ExaminerGary L. Smith Akron, Ohio Attorney-William Cleland 22 F! d: S t. 21 1970 1 57 ABSTRACT [211 App! 73749 A tool for forcibly releasing interlocked work parts,

such as a frozen piston from a disc-brake caliper. The

[52] U.S. CI. 29/263 tool includes a fi separable, igi t p r f r en- [51] Int. Cl 823 19/04 g g wi h n work p -pi r gi se nd [58] Field of Search 29/258, 259, 263, tool par in engagement with the other Work P and 29/265, 266, 280 a connector means connected between the first and second tool parts and including screw means for axially [56] References Cited adjusting the first and second tool parts toward one an- UNTED STATES PATENTS other to separate the interlocked work parts. 3,579,796 5/1971 Fillion 29/263 10 Claims, 4 Drawing Figures 1 l I u 1 2 i I 4 I l 4 l i V W l {6a :*"IT:T F' 15' a 18 f Z5 L i e F I F I 31,3 2 Li f f i H L "7 "IF /Z I I I /3 y e K3 W I PATENTEU INVENTOR. George Racm BY wi Nd'o ney 1 TOOL FOR RELEASING FROZEN WORK PARTS BACKGROUND OF THE INVENTION I-Ieretofore, in repairing disc-brakes for example, considerable difficulty has been encountered in the removal of frozen pistons from the so-called brake calipers, namely a part of the brake in which a small cupshaped piston is fluid-operated to apply braking pressure between interengageable disc-brake parts. Previously no suitable tool has been available on the market for accomplishing this operation, and the piston was usually removed with difficulty, as by hammering an exposed extent of the piston and/or by using lever type tools which only tended to bind the piston further. Plier type tools, applied outside or inside the piston to turn the same, were also quite ineffective because of slippage. All in all, the known prior art devices for this purpose tended to aggravate the difficulty, and often damaged the piston by breaking or cracking the same. Quite often it was necessary to replace both the caliper and the piston or pistons.

SUMMARY OF THE INVENTION The present invention has for its main object the provision of a tool for forcibly separating frozen work parts, such as a piston which has been frozen against reciprocation in the so-called caliper of a disc-brake of an automobile. The present invention is for a new tool including a hollow, cup-shaped cap having an adjusting rod or bolt threaded through the closed end of the cap, and a smaller segmental cap separably supported on an enlargement on the inner end of the bolt, and adapted to be withdrawn into the larger cap by threaded operation of the adjusting rod, in use of the tool, or for retaining the parts of the tool when it is not in use.

The tool is used for removing a frozen piston, for example, by engaging the segmental cap with an exposed portion of the piston while the threaded rod is fully extended through the larger cap, to lock complementally interengaging portions of the segmental cap and the piston together, and then turning the threaded rod to draw the larger cap toward stop engagement of the lower edge of a peripheral wall of larger cap with the caliper. With continued forcible turning of the rod the smaller cap is in effect drawn into the larger cap, uniformly to apply sufficient force in axial direction to pull the piston from the caliper.

Objects of the invention will be manifest from the following brief description and the accompanying drawings.

Of the accompanying drawings:

FIG. 1 is a front elevation, partly broken away and in cross-section, of the improved tool in an initial position in relation to a disc-brake caliper, (indicated in single dot chain-dotted lines) in which the piston is gripped by one part of the tool.

FIG. 2 is a top plan view of FIG. 1.

FIG. 3 is a front elevation, partly broken away and in section, corresponding generally to FIG. 1, in which a second part of the tool is screw actuated into engagement with the caliper, for further separation of the tool parts to remove the piston from the caliper, as indicated in double dot chain-dotted lines.

FIG. 4 is a horizontal cross-section, taken substantially on the line 4-4 of FIG. 3.

Referring first to FIGS. 1 and 2, there is illustrated a three part tool for removing a cup-shaped piston I1 which is frozen within a cylindrical cavity 12 of a caliper 13 ofa disc-brake unit of known type. A portion of the piston 11 projecting above a peripheral upper surface 14 of the caliper, has an radially outwardly presented annular groove 15 therein, defining shoulder means for purposes to be described.

The improved tool 10 may comprise a first tool part 16 of inverted cup-shape, having a centrally apertured top wall 17, and cylindrical outer wall 18, terminating at the lower edge thereof in an integral annular rib or flange, or arcuate jaws, 19 for complemental reception within the groove or shoulder means 15 of the piston 11. A second inverted cup-shaped tool part 20 may include a top wall 21 having a central boss or stop means 22, through which an elongated connecting means, such as a bolt or screw 23 is adjustably threaded to extend through the central aperture 24 of the first tool part 16, said screw having a stop means or enlargement or head 25 for supporting engagement with the underside of the top wall 17 of tool part 16. The first tool part 16 may comprise discrete, complementally engaged half segments 16a, 160, which are adapted to be radially moved apart, for purposes to be described later, as shown in chain-dotted lines in FIG. 1.

In use of the improved tool 10 for removing a piston 11 frozen within the cavity 12 of a brake caliper 13, the tool in the full line condition shown in FIG. 1 is lowered toward the top of the piston 11 while supported by one hand, while the other hand is used to momentarily separate the discrete, half sections 16a of the first tool part 16, and then to press the sections together about the top of the piston with the rib portions 19 inserted in the annular channel 15 of the piston (see full and chaindotted lines in FIG. 1).

Next, the second tool part 20 may be manually turned on the screw 23 until the lower edge of the annular wall 20a firmly engages the top wall surface 14 of the caliper l3 and surrounds the first tool part 16, as shown in full and single-dot chain-dotted lines in FIG. 3. Now, by turning the screw 23, using a suitable wrench (not shown) on the gripping nut or head 23a, the second tool part 20 will be urged downwardly against the fixed resistence of the caliper wall portion 14 until the screw starts to pull the first tool part 16 upwardly. With continued turning of the screw the tool part 16 will eventually be uniformly pulled from the caliper cavity 12, as shown in full and double-dot chain-dotted lines in FIG. 3. When the piston 11 has been so extracted, it may be released from the tool by turning bolt 23 back to the extended condition shown in full lines in FIG. I, to permit the aforesaid separation of the segments 16a (see chain-dotted lines). Obviously, the second tool part may be turned instead of the bolt 23, if desired, so long as there is relative rotation between the second tool part and the bolt.

When the tool is not in use the parts may be adjusted back to the full-line retracted condition shown in FIG. 3, for containing the segments against possible loss. This feature of the invention may be further improved as by magnetizing the adjoining, mating edges of the segments 16a to draw and hold the segments together in all the conditions shown in FIGS. 1, 3, and 4.

Other Modifications of the invention may be resorted to without departing from the spirit thereof or the scope of the appended claims.

What is claimed is:

l. A tool as for forcibly releasing a frozen brake piston from a cylindrical cavity of a disc-brake caliper, wherein said exposed end of the piston is provided with an axially inwardly presented annular shoulder means, and the caliper has axially outwardly exposed shoulder means, said tool comprising: a generally cup-shaped first tool part adapted to be cupped over said exposed end of the brake piston, and being composed of separable discrete, rigid parts provided with radially inturned, arcuate jaws of substantial peripheral extent for rigid complemental engagement with a major peripheral extent of the annular shoulder means of the piston; a second, one-piece, rigid tool part having integral, downwardly presented peripheral portions adapted supportand thereby, through resultant axially outward force of said arcuate jaws applied to said shoulder means of the piston, to separate the frozen piston from the brake caliper.

2. A tool for forcibly separating a piston from a cylindrical cavity in a housing, wherein an exposed end portion of said piston has an axially inwardly presented annular shoulder and the housing has an axially outwardly presented shoulder, said tool comprising a generally cup-shaped first tool part adapted to be cupped over said exposed end of the piston, said first tool part including separable, discrete, rigid parts each having radially inturned arcuate jaws thereon engageable with the inwardly directed shoulder of said piston, a rigid one-piece second tool part having an internally threaded portion and downwardly presented peripheral portions engageable with the outwardly presented shoulder of the housing to support the threaded portion of the second tool part in spaced relation to the piston, and an axially elongate, solid, rigid, externally threaded connetor means axially connected between the first tool part and the second tool part, said connector means threadably engaged with the threaded portion of said second tool part for relative rotation between the second tool part and connector means and resultant axial adjustment therebetween, and said connector means connected to said first tool part through a stop abutment so that relative axial movement between the connector means and first tool part is precluded, relative rotation in one direction between said second tool part and said connector means resulting in axial adjustment of said first and second tool parts toward one another and outward force on the shoulder means of said piston to separate the piston from the cylindrical cavity.

3. A tool as in claim 1, wherein said connector means is a solid, one-piece bolt, tool engaging means on one end of the bolt, and said first stop connection is on the other end of the bolt, said first stop connection comprising an enlarged head presenting a peripheral axially facing shoulder engageable with the first tool part.

4. A tool as in claim 1, wherein the first tool part comprises a pair of mating half segments each having an arcuate side wall, an end wall on one end of the side wall, and said inturned flange on the other end of the side wall.

5. A tool as in claim 1, wherein the second tool part is substantially cup-shaped and has a disc-shaped end wall and an annular, axially extending cylindrical side wall with a downwardly projected free end, said downwardly presented peripheral portions being on the free end of the annular wall.

6. A tool as in claim 1, wherein the second stop connection comprises a threaded portion of the second tool part.

7. A tool as in claim 6, wherein the second tool part includes a disc-shaped wall, said second stop connection disposed centrally of said disc-shaped wall, and said elongate connector means extending through an aperture in the center of the disc-shaped wall and threadably engaged with the second stop connection.

8. A tool as in claim 1, wherein the second tool part is substantially cup-shaped and includes a disc-shaped end wall and a cylindrical, axially extending, peripheral side wall, the downwardly presented peripheral por tions being on the free end of the side wall, said first tool part including a pair of substantially identical half segments each having an end wall portion and an arcuate side wall portion, said end wall portions engageable with said first stop connection, said elongate connector means extending axially through the disc-shaped end wall of the second tool part and threadably engaged therewith.

9. A tool as in claim 8, wherein said second stop connection comprises an internally threaded, integral, upstanding boss in the center of said disc-shaped end wall, said cylindrical side wall of the second tool part having an internal diameter greater than the external diameter of the first tool part, and defining a recess for the reception of said first tool part when said first tool part is drawn toward said second tool part upon axial adjustment of said elongate connector means through said threaded boss.

10. A tool as in claim 1, wherein said first tool part comprises a pair of half segments, means on said segments for retaining said segments assembled on said elongate connector means and in engagement with said first stop means. 

1. A tool as for forcibly releasing a frozen brake piston from a cylindrical cavity of a disc-brake caliper, wherein said exposed end of the piston is provided with an axially inwardly presented annular shoulder means, and the caliper has axially outwardly exposed shoulder means, said tool comprising: a generally cupshaped first tool part adapted to be cupped over said exposed end of the brake piston, and being composed of separable discrete, rigid parts provided with radially inturned, arcuate jaws of substantial peripheral extent for rigid complemental engagement with a major peripheral extent of the annular shoulder means of the piston; a second, one-piece, rigid tool part having integral, downwardly presented peripheral portions adapted supportively to overlie and engage the exposed caliper shoulder means; and axially elongated, rigid connector means axially connected between said first and second tool parts, and the rigid connector means having thereon axially spaced first and second stop connections with said first and second tool parts, respectively, and including screw means operable by relative rotation between said connector means and said second stop connection with said second tool part, for axially adjusting the spacing of the first and second tool parts and thereby, through resultant axially outward force of said arcuate jaws applied to said shoulder means of the piston, to separate the frozen piston from the brake caliper.
 2. A tool for forcibly separating a piston from a cylindrical cavity in a housing, wherein an exposed end portion of said piston has an axially inwardly presented annular shoulder and the housing has an axially outwardly presented shoulder, said tool comprising a generally cup-shaped first tool part adapted to be cupped over said exposed end of the piston, said first tool part including separable, discrete, rigid parts each having radially inturned arcuate jaws thereon engageable with the inwardly directed shoulder of said piston, a rigid one-piece second tool part having an internally threaded portion and downwardly presented peripheral portions engageable with the outwardly presented shoulder of the housing to support the threaded portion of the second tool part in spaced relation to the piston, and an axially elongate, solid, rigid, externally threaded connetor means axially connected between the first tool part and the second tool part, said connector means threadably engaged with the threaded portion of said second tool part for relative rotation between the second tool part and connector means and resultant axial adjustment therebetween, and said connector means connected to said first tool part through a stop abutment so that relative axial movement between the connector means and first tool part is precluded, relative rotation in one direction between said second tool part and said connector means resulting in axial adjustment of said first and second tool parts toward one another and outward force on the shoulder means of said piston to separate the piston from the cylindrical cavity.
 3. A tool as in claim 1, wherein said connector means is a solid, one-piece bolt, tool engaging means on one end of the bolt, and said first stop connection is on the other end of the bolt, said first stop connection comprising an enlarged head presenting a peripheral axially facing shoulder engageable with the first tool part.
 4. A tool as in claim 1, wherein the first tool part comprises a pair of mating half segments each having an arcuate side wall, an end wall on one end of the side wall, and said inturned flange on the other end of the side wall.
 5. A tool as in claim 1, wherein the second tool part is substantially cup-shaped and has a disc-shaped end wall and an annular, axially extending cylindrical side wall with a downwardly projected free end, said downwardly presented peripheral portions being on the free end of the annular wall.
 6. A tool as in claim 1, wherein the second stop connection comprises a threaded portion of the second tool part.
 7. A tool as in claim 6, wherein the second tool part includes a disc-shaped wall, said second stop connection disposed centrally of said disc-shaped wall, and said elongate connector means extending through an aperture in the center of the disc-shaped wall and threadablY engaged with the second stop connection.
 8. A tool as in claim 1, wherein the second tool part is substantially cup-shaped and includes a disc-shaped end wall and a cylindrical, axially extending, peripheral side wall, the downwardly presented peripheral portions being on the free end of the side wall, said first tool part including a pair of substantially identical half segments each having an end wall portion and an arcuate side wall portion, said end wall portions engageable with said first stop connection, said elongate connector means extending axially through the disc-shaped end wall of the second tool part and threadably engaged therewith.
 9. A tool as in claim 8, wherein said second stop connection comprises an internally threaded, integral, upstanding boss in the center of said disc-shaped end wall, said cylindrical side wall of the second tool part having an internal diameter greater than the external diameter of the first tool part, and defining a recess for the reception of said first tool part when said first tool part is drawn toward said second tool part upon axial adjustment of said elongate connector means through said threaded boss.
 10. A tool as in claim 1, wherein said first tool part comprises a pair of half segments, means on said segments for retaining said segments assembled on said elongate connector means and in engagement with said first stop means. 